Concepts Of Lifetime Fitness

Concepts of Lifetime Fitness
September 1, 1997
Homeostasis is the state of equilibrium in which the internal environment of the human body
remains relatively constant. Two excellent examples of homeostasis are how the body maintains a constant
temperature and blood pressure during strenuous physical activity or exercise. Although there are many
other activities in the body that display homeostasis, I will only discuss these two.
Temperature in the human body is usually kept at approximately 37 degrees Celsius. To maintain
such a strict temperature, the body has a few functions to combat the outside elements. People cannot
make themselves cold as readily as make themselves hot, however I will mention both homeostasis
functions. When the external temperature decreases, a portion of the brain called the hypothalamus detects
the drop by means of the blood. To compensate, the brain sends chemical and electrical impulses to the
muscles. These impulses tell the muscles to begin to contract and relax at very high intervals. This is
commonly known as shivering. The production of Adenosine Triphosphate or ATP in the mitochondria of
the muscles produces heat. If the body temperature does not rise immediately after this, then a second
function begins. The brain will signal the blood vessels near the skin to constrict or narrow in diameter.
This occurs so the heat deep in the muscles is conserved. Sinc!
e the vessels are now smaller in diameter, less blood is...

Concepts Of Lifetime Fitness

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